- High frequency PCBs are ideal for applications that involve special signal transmissions between devices
- These PCBs also involve the use of special materials to achieve a high frequency
- High frequency PCBs produce high frequency signals that have tighter impedance when compared to conventional PCBs
What is High Frequency PCB?
Are you dealing with wireless networks or applications that include particular signal transmission amid objects? Then consider getting a high-frequency PCB.
These PCBs come in a frequency range of 500MHz to 2GHz. You can use them in different applications like high-speed design applications, microwaves, mobiles, etc.
There’s a lot of signal sensitivity that comes with this type of PCB. Thus, it has high-frequency laminates that help to sustain the thermal heat transfer of the application.
Also, the type of high-frequency board you choose will determine the overall performance of your signal. If there’s any change in the material’s dielectric constant, it will affect your board’s impedance.
Key Features of High
The Required Materials for High
Frequency Circuit Board
High-frequency circuit boards have specific demands on the materials they use. So, a great example is its improved permittivity.
We also have other needs similar to construction with reduced tolerance in DK and insulation thickness. It also includes a reduced attenuation for competent signal transmission.
We choose an adequate layer buildup for most of our applications and use FR4 material (considering that it’s sufficient to use). Also, we use enhanced dielectric properties to process high-frequency materials.
And it’s because it’s frequency independent, has a low DK, and low loss factor. Other properties that we include are an extremely low hydrophilic rate, high glass transition temperature, and remarkable thermal durability.
Some of the materials we use are Taconic TLX, Rogers, ISOLA IS620 E-fiber glass, etc.
Here’s a table that explains each of the material’s properties:
|Materials for HF circuit boards||Tg (℃)||CTE-z (PPM/℃)||Peel Strength(N/mm)||Td Value (℃)||DK Loss Tangent||Thermal Conductivity (W/m*K)||Surface Resistivity(MΩ)||Electric Strength (KV/mm)||Ԑr (@10GHz|
|ARLON 85N||250||55||1.2||387||0.0100||0.20||1.6 x 10^9||73||4.2|
|Rogers 4350B||280||32||0.9||390||0.0037||0.69||5.7 x 10^9||31||3.5|
|Rogers RO3010||–||16||1.6||500||0.0022||0.95||1 x 10^5||–||10|
|ISOLA IS620||220||54||1.2||–||0.0080||–||2.8 x 10^6||–||4.5|
|Rogers RO3006||–||24||1.2||500||0.0020||0.79||1 x 10^5||–||6.2|
|Rogers RO3003||–||25||1.2||500||0.0013||0.50||1 x 10^5||–||3.0|
|Rogers RO3001||160||–||2.1||–||0.0030||0.22||1 x 10^9||98||2.3|
|Taconic TLC||–||70||2.1||–||–||0.24||1 x 10^7||–||3.2|
|Taconic TLX||–||135||2.1||–||0.0019||0.19||1 x 10^7||–||2.5|
Applications of High
Antennas and power amplifiers
RF identification tags
Automotive radar systems
Global positioning satellite antennas
Why You Should Consider Getting
High Frequency PCB
–With a high-frequency PCB, you can get a lot of benefits like:
The Guidelines for High Frequency
PCB Design & Layout
–The sure ways to achieve a reasonable layout plan and suitable wiring for a high-frequency PCB include:
1. Fewer vias in your connection
Ensure that you have fewer vias in your connection because when you use a via, it produces a distribution capacitance of 5 x 10-13F. So, reducing the via leads to a drastic increase in speed. Plus, it decreases the chance of having data errors.
2.Make a high-frequency lead longer
In this step, the science is that the signal line’s routing length is directly proportional to the radiation intensity. With that in mind, it means that when the high-frequency lead is longer, you’ll find it easy to couple its parts.
3.Reduce the bend
Reduce the bend that exists between the pins on the high-frequency board. Most times, it’s ideal to use a full straight line when you’re wiring the HF boards. If you must have a break over, use an arc break or a broken line at 45 degrees. Consequently, you’ll enhance the copper foil’s bonding strength in low-frequency circuits. But this step isn’t necessary for high-frequency circuits. And it’s because it decreases the outer emissions.
4.Reduce the crosstalk
Don’t take the crosstalk from the signal line for granted. The crosstalk occurs between signal lines that lack a direct connection. So, it’s best to reduce the crosstalk that occurs in high-frequency signals.
5. Try not to have loops
Try not to have loops when you’re wiring the HF board. If they occur, make them extremely small.
The Few Bottlenecks with
Manufacturing HF Boards
–Some of the slight challenges you may encounter with HF boards include:
Copper Foil Finish for High Frequencies
When there is an increase in frequency, the signal flows through the track. And the track produces current. Then, the current pushes current density to the outer surface instead of the center of the track. So, during production, you may experience increased roughness of the copper surface. As a result, there will be loads of signal losses at high frequencies.
Solder Mask at High Frequencies
Soldermask has a high dissipation factor. So, when you apply it on traces with high frequency, it boosts the circuit’s dielectric loss.
How to Produce Controlled
Impedance Transmission Lines?
–The aim of creating controlled impedance is to avoid signal loss. And there are two simple ways you can achieve that goal:
This method has to do with having the trace on the top layer. And the trace usually has a ground plane under it.
The calculation involved in this method is quite complicated. Plus, it relies on different factors like height above the plane, relative permittivity, width of the trace, etc. So, your best option is to ensure that your ground plane is quite close to the top layer.
The stripline method is similar to the microstrip, and the only difference is that the stripline has an additional group plane. And the group plane is on top of the trace. While using this method, ensure that you put the trace between the two planes. This method is a better option. And the reason is that within the two planes, there’s EMI radiation.
WELLPCB- Your High-Frequency
WellPCB has a wealth of experience in the field of PCB production. So, you can trust that you’ll get remarkable performing high-frequency PCB fabrication services. And our board usually ranges from 500MHz to 2GHz.
Here’s a table to give you an idea:
Thickness of board:0.4 – 5.0 mm
PP:Domestic- (6700), Rogers 4450F, etc.
Silkscreen sides:It depends on the file.
Number of layers:2 – 32 layers
Alternative methods:Countersink holes, Gold fingers, Peelable solder, mask Carbon oil
Silkscreen color:Black, yellow, white
Surface finish:Immersion tin – RoHS, ENIG – RoHS, Organic solderability preservatives – RoHS, Immersion silver – RoHS
Build time:It depends on the project (2 days to 5 weeks)
Material:RO3010, RO4350B, RT5880, RO4003C, RO3003
Order quantity:1 – 10000+pcs
Solder mask color:Blue, red, yellow, green, white
Quality grade:Standard IPC 2
Board size:0.4-5.0 mm
Min drill hole diameter:6mil
Finished copper weight:0.5 – 2.0 0z
Min annular ring:4mil
1. How to choose the board material of high frequency pcb/High-speed PCB Materials?
For the selection of materials, FR-4 material is the common laminate material. Other substrate materials, except for alumina substrates, like PPO and Teflon are also in use as frequency laminates. Furthermore, you also need to consider the material combinations, dielectric material, carrier substrate of the PCB substrate.
2. How about the signal integrity issues in high-frequency signal transmission?
Signal integrity is to measure these signal distortions in the high-frequency regime. signal traces, the signal layer, and signal energy may affect the efficient signal transmission. For more about the high-speed signal, please contact our team.
3. What to consider in the High-speed PCB design/High-frequency designs?
First, consider circuit designs’ design rules such as PCB layout design, the design process in the electronics design. Besides, your high-frequency applications determine the circuit performance you need. Such as characteristic impedance, mechanical strength, thermal characteristics (thermal expansion), chemical resistance, loss tangent, heat dissipation. Then, layer thickness, PCB Component (critical components) of the electronic device, digital circuitry, conductive layers. Also, antenna arrays, antenna efficiency, conductor losses are also important factors to consider.